-- Discussion containing changed information from previous version are highlighted. --
317
FXUS64 KMRX 192300 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
700 PM EDT Thu Sep 19 2024

...New AVIATION...

.SHORT TERM...
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(This evening through Friday)
Issued at 314 PM EDT Thu Sep 19 2024

Key Messages:

1. A few isolated to scattered showers, and possibly a storm,
through early evening.

2. Patchy to areas of fog overnight.

3.  Dry and warmer tomorrow, with temperatures around 5 to 8 degrees
above normal.

Short term models did a poor job earlier today with the current
showers across the area. Models kept precip east of I-75 and mainly
across our higher terrain areas. Based on latest radar trends and
CU field, went ahead and put in a 15 (Slight Chance) POP for most
areas through early evening. Most locations will remain dry, but
some may cash in on a quick downpour.

Tonight, dry with patchy to areas of fog developing after midnight.
This will be especially true for any areas that receive a shower
this afternoon and evening.

Tomorrow, expect a dry day with warmer temperatures as the ridge
further builds across the area. Temperatures will be around 5 to 8
degrees above normal. Went a little lower with dewpoints tomorrow
based on today`s trends. Went with NBM10. Based on the higher temps,
we can expect min RH values down in the mid to upper 30s for some
areas. Winds remain light though which will help to alleviate most
fire weather concerns.
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&&

.LONG TERM...
(Friday night through next Thursday)
Issued at 314 PM EDT Thu Sep 19 2024

Key Messages:

1. Continued well above normal temperatures (5 to 10F) through the
middle of next week.

2. Higher uncertainty for next week, but expect moderating
temperatures with gradual increase in rain chances.

Discussion:

Upper-level 500mb 590-591 dam ridge across the Southern Plains and
Lower Mississippi Valley will result in dry and warm weather into
the Tennessee Valley through the weekend. Northwest flow aloft and
subsidence will bring clear sky conditions and plenty of sunshine.

A stronger shortwave will approach the Ohio Valley by the middle of
next week with an associated surface low and cold front approaching
the Tennessee Valley on Tuesday or Wednesday. Current PoPs are
limited to 30 to 40 percent, and a look at the ensembles histogram
shows that most of these members are placing around 0.25 inch or
less across the region. Only about 15 percent of members have more
than one inch of QPF, and with the westerly zonal flow ahead of the
front, a drier solution appears more probable. If the cold front can
make it through the area, some cooler, near normal, air would be
likely late next week.

&&

.AVIATION...
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(00Z TAFS)
Issued at 659 PM EDT Thu Sep 19 2024

Chance of fog appears high at TRI tonight, based on last night`s
fog plus afternoon dewpoints in the mid 60s, and a forecast low of
60. Model guidance is alo pointing to 1/4SM vis for a few hours
late tonight and Friday morning. TYS has a lower chance of fog on
the same basis, and the TAF will have MVFR vis there. Lower
dewpoints today at CHA and dry ground conditions suggest fog is
unlikely to develop.
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&&

.PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN             89  66  92  65 /  10   0   0   0
Knoxville McGhee Tyson Airport, TN  87  63  89  63 /  20  10   0   0
Oak Ridge, TN                       89  62  89  63 /  20  10   0   0
Tri Cities Airport, TN              83  60  84  60 /  20  10   0   0
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&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

SHORT TERM...
LONG TERM....JB
AVIATION...DGS